Question

Complete the following table:

Group of Algae	Chlorophyceae	Phaeophyceae	Rhodophyceae
Stored food	Starch
Cell wall		Cellulose and algin
Major Pigments			Chlorophyll- a,b; phycoerythrin.

Answer 1

Hint: Algae are the photosynthetic eukaryotic organisms. Algae are generally aquatic and are autotrophs. The algae have chloroplasts that are similar to that of cyanobacteria. They also have circular DNA in their chloroplast. Algae do have structure like that of land plants.

Complete answer:
Macroalgae is classified in three major groups based on the colour of the organism.
i) Chlorophyceae- These are green algae which have a distinct morphology. They differ from other classes by the arrangement of flagella. They are green in colour due to the pigment Chl-a and b. They have storage bodies called pyrenoids in their chloroplast. The stored food is in the form of starch. Feb species of this class also store oil droplets. They have rigid cell walls with the presence of cellulose.
ii) Phaeophyceae-These are brown algae which are mainly multicellular. They usually thrive in the marine environment. The chloroplast of phaeophyceae is surrounded by four membranes. These organisms show symbiotic relationships with other eukaryotes. The cell wall of phaeophyceae is made up of cellulose and algin. The brown colour is due to the pigment called fucoxanthin. The food is stored in the form of laminarin or mannitol.
iii) Rhodophyceae-These are red algae due to the pigment called phycoerythrin in their body. They do not have flagellated cells. They store food in the form of Floeidian starch. The cell membrane is made up of cellulose.

The correct answer is

Group of Algae	Chlorophyceae	Phaeophyceae	Rhodophyceae
Stored food	Starch	laminarin or mannitol	Floeidian starch
Cell wall	cellulose	Cellulose and algin	cellulose
Major Pigments	Chlorophyll-a, b	fucoxanthin	Chlorophyll- a,b; phycoerythrin.

Note: The red algae help in carbon fixation. They are edible and are an important source of food. Red algae produce agar which is used as a food additive. Algae produces around 30-50% of net oxygen production which is utilised by terrestrial animals and humans.